The present invention relates to linear polyalkylorgano-siloxanes having polyoxyalkylene and amino-functional groups which additionally have terminal alkoxy groups, and to the preparation and use thereof.
It is known that aminosiloxanes having primary and secondary nitrogen groups and sometimes reactive silanol groups are incorporated as conditioning agents into hair shampoo formulations. These products are in most cases in the form of a mixture with the aid of surface-active substances in water. Purely in their original form, they are not soluble in water. They are solubilized in water by surface-active substances (emulsifiers, for example primary, multiple, secondary or tertiary surfactant systems) and converted into an aqueous emulsion. These surface-active substances usually consist of ethoxylated fatty alcohols, ethoxylated glycerides, fatty acid esters or similar products. Various products are available commercially, in particular from Dow Corning under the names DC 929, DC 949 and DCQ 2-8220. Products which as such are not soluble in water without the addition of surface-active substances are also available commercially from General Electric, e.g. under the name SME 253.
In order to improve the solubility in water, the aminosiloxanes can additionally be substituted by polyoxyalkylene groups. For example, U.S. Pat. No. 5,075,403 describes polydialkylorganosiloxanes which carry amino and polyoxyalkylene groups. Such products are prepared by cohydrosilylation of allylamines and allyl polyethers to hydridopolydimethylsiloxanes. However, it is observed here that the hydrosilylation reaction often does not achieve the desired conversions and so the desired degree of modification along the polydimethylsiloxane chain cannot be established.
It is also observed that aminosiloxanes which carry additional polyoxyalkylene groups for the most part remain in the aqueous phase upon use and do not attach to the hair in the desired manner.
In addition, in the case of aminosiloxanes, it is generally observed that an unpleasant odor adheres to the products as a result of the liberation of traces of volatile amines. These odors are undesired in the field of cosmetics. If attempts are made to remove the odor by distillation, it is generally observed that the unpleasant odor returns after a short period.
The object of the present invention was to prepare conditioning agents based on hydrophilic polydialkylorganosiloxanes which contain aminosiloxane groups, have a mild odor and exhibit lasting conditioning properties within the hair.
Surprisingly, it has been found that linear polyalkylorgano-siloxanes having polyoxyalkylene and amino-functional groups which additionally have terminal alkoxy groups exhibit a greatly improved hydrophilicity and have excellent conditioning properties.
It has also been found that the synthesis of linear polyalkylorganosiloxanes having polyoxyalkylene and amino-functional groups by alkaline equilibration leads to products having terminal alkoxy groups and problems with incomplete conversions are avoided.
The present invention thus provides linear polydialkylorganosiloxanes having polyoxyalkylene and amino-functional groups which additionally have terminal alkoxy groups, of the general formula (I) 
where
a=5 to 500 and
b=1 to 100 and
the radicals
R1=identical or different aliphatic or aromatic hydrocarbon radicals having up to 8 carbon atoms,
R2=R1, R2a or R2b, with the proviso that on statistical average a radical R2a is present in at least every tenth siloxane chain, and at least one radical R2b is present in each siloxane chain,
where
the radical R2a is chosen from the radicals of an amino-functional group of the general formula (II)
xe2x80x94[(R4)cxe2x80x94NR5]dxe2x80x94R6
xe2x80x83where
R4=a divalent C1 to C12 hydrocarbon radical, an xe2x80x94OCH2CH2xe2x80x94 group or an OCH2CH(CH3)xe2x80x94 group,
R5=a monovalent C1 to C12 hydrocarbon radical or a hydrogen atom,
R6=a monovalent aliphatic or aromatic, optionally substituted C1 to C12 hydrocarbon radical or a hydrogen atom,
where
c=1 to 10
d=1 to 5,
the radical R2b is a polyoxyalkylene group of the general formula (III)
xe2x80x94(CH2)e(OC2H4)f(OC3H6)gOR6
xe2x80x83where
e=2 to 10
f2 to 20
g=0 to 20 and
R3=R1 or a group of the general formula (IV)
xe2x80x94OR1
with the proviso that on statistical average at least one radical of the general formula (IV) is present on the siloxane backbone.
The present invention further describes the synthesis of hydrophilic polysiloxanes to which amino and polyoxyalkylene chains are linked at the same time via Sixe2x80x94C bonds.
In a preferred embodiment of the present invention, the polyalkylorganosiloxanes are those in which
a=a number in the range from 5 to 100, in particular 10 to 50,
b=a number in the range from 3 to 50, in particular 3 to 30 and
c=a number in the range from 1 to 10, in particular 1 to 6.
For the purposes of the present invention, particular preference is given to polydialkylorganosiloxanes where in the general formula (I) the radical R1 is a methyl radical.
As stated above, it is a necessary condition that on statistical average at least one of the groups R2b and R3xe2x95x90xe2x80x94OR1 is present in each molecule of the polydialkylorganosiloxanes, and a radical R2a is present at least in every tenth siloxane chain. For the purposes of the present invention, it is particularly preferred if the molar ratio of the groups R2a to R2b to R3xe2x95x90xe2x80x94OR1 is 0.5 to 2 to 1.
A further preferred embodiment of the present invention consists in the process for the preparation of the polyalkyldiorganosiloxanes defined above. For the purposes of the present invention, the latter are prepared, for example, by equilibrating a mixture of a suitable polyethersiloxane of the general formula 
and/or a cyclic polyethersiloxane of the general formula 
where R1, R2band b are as defined above and axe2x80x2 =0 to 500, a suitable dialkoxyaminosilane and/or its partial hydrolyzate, optionally octamethylcyclotetrasiloxane and/or decamethylcyclopentasiloxane using a basic catalyst.
The basic catalysts are, in particular, catalysts, such as alkali metal hydroxides, in particular sodium, potassium and cesium hydroxides, alkali metal alkoxides, quaternary ammonium hydroxides, such as tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzyltrimethylammonium butoxide, xcex2-hydroxyethyltrimethylammonium 2-ethylhexoate, quaternary phosphonium hydroxides, such as tetra-n-butylphosphonium hydroxide and tri-n-butyl-3-[tris(trimethylsiloxy)silyl]-n-propylphosphonium hydroxide, alkali metal siloxanolates and ammonium organosiloxanolates, such as benzyltrimethylammonium siloxanolate and tetramethylammonium siloxanolate.
Use is preferably made of 10 ppm to 1% by weight, in particular 50 to 2 000 ppm, of basic catalyst, in each case based on the weight of the total mixture.
The dialkoxyaminosilanes preferably have the general formula
(R1)(R1O)2Si(R2a)
in which
R1, R2a are as defined above.
Examples of dialkoxyaminosilanes are N-aminoethyl-3-aminopropylmethyldimethoxysilane, N-aminoethyl-3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane and/or 3-aminopropylmethyldiethoxysilane.
Partial hydrolyzates of the dialkoxyaminosilanes are prepared in a preceding reaction step by condensation of the aminosilanes with water, those partial hydrolyzates having up to 30 silicon atoms being preferred.
Also described is the use of the compounds according to the invention for the preparation of haircare formulations, such as conditioning formulations (xe2x80x9cconditionersxe2x80x9d), hair rinses, conditioning shampoos, and conditioning agents which remain in the hair following application (xe2x80x9cleave-inxe2x80x9d products). The present invention likewise relates to the use of the compounds according to the invention for the treatment of textile surfaces and of natural and/or synthetic fibers and/or xe2x80x9cnonwovenxe2x80x9d materials, in particular for improving the soft feel and the hydrophilicity.
The polydialkylorganosiloxanes according to the invention are also suitable for the preparation of surface-active formulations, where the surfactant is chosen from the group of anionic surfactants, cationic surfactants, nonionic surfactants and/or amphoteric surfactants.
The polydialkylorganosiloxanes according to the invention have only a low tendency to form nitroamines, even in the presence of primary or secondary amines.